A new fluorescent chemosensor P from 5-(thiophen-2-yl)oxazole-4-carbohydrazide and 4-diethylaminosalicylaldehyde was designed and synthesized for sequential detection of In³⁺ and Cr³⁺ ions. P exhibits strong fluorescence enhancement at 512 nm upon binding to In³⁺. The green fluorescence of complex P-In³⁺ was selectively quenched by Cr³⁺. The complex stoichiometry of P with In³⁺ and Cr³⁺ was identified as 1:2 for both in conjunction with Job’s Plot analysis, ESI-MS titration and theoretical calculations. Moreover, P was successfully applied to monitor target ions in actual water samples, and a portable paper sensor for the detection of In³⁺ was investigated to evaluate the versatility application.

设计并合成了一种由 5-(thiophen-2-yl)oxazole-4-carbohydrazide 和 4-diethylaminosalicylaldehyde 组成的新型荧光化学传感器P，用于顺序检测 In ³⁺和 Cr ³⁺离子。P在与 In ³⁺结合后在 512 nm 处表现出强烈的荧光增强。^{配合物P-In 3+}的绿色荧光被Cr ³⁺选择性猝灭。结合 Job's Plot 分析、ESI-MS 滴定和理论计算，P与 In ³⁺和 Cr ³⁺的复杂化学计量被确定为 1:2。此外，成功应用于监测实际水样中的目标离子，并研究了用于检测 In ^{3+的便携式纸质传感器，以评估其多功能性应用。}